1. Field of the Invention
The present invention relates to high-frequency signal lines and manufacturing methods thereof, more particularly to high-frequency signal lines preferably for use in transmission of high-frequency signals and manufacturing methods thereof.
2. Description of the Related Art
One known example of an invention relating to the conventional high-frequency signal lines is a high-frequency signal line disclosed in Japanese Patent Laid-Open Publication No. 2011-071403. This signal line includes a main body, a signal line, and two ground conductors. The main body is formed by laminating a plurality of insulating sheets which are made of a flexible material and linearly extending in a predetermined direction. The signal line is a linear conductor provided on the insulating sheets. The two ground conductors are provided on the insulating sheets. The signal line is provided between the two ground conductors in terms of the direction of the lamination. With this arrangement, the signal line and the two ground conductors form a stripline structure. The high-frequency signal line is used for, for example, connection of two circuit boards included in an electronic device.
In manufacturing the above-described signal line, a signal line and two ground conductors are formed on a plurality of large-sized mother insulating sheets, and the plurality of mother insulating sheets are laminated such that the signal line is provided between the two ground conductors, such that a mother laminate is formed. Then, the mother laminate is stamped (cut) out, such that a plurality of signal lines are simultaneously manufactured. To obtain a larger number of signal lines from a single mother laminate, a plurality of signal lines are arranged in a matrix over the mother laminate with the gap between adjacent signal lines being as small as possible.
For convenience of the layout of circuit boards, a battery pack, a liquid crystal panel, etc., inside electronic devices, it is preferred in some cases that the signal line disclosed in Japanese Patent Laid-Open Publication No. 2011-071403 has a bent configuration, such as L-shape or U-shape, when viewed in plan in the direction of the lamination. When such bent signal lines are arranged over the mother laminate, the gap between adjacent signal lines is large as compared with a case where linear signal lines are arranged over the mother laminate. Accordingly, the number of signal lines obtained from a single mother laminate decreases, and the manufacturing cost of the signal lines increases.